Mitochondrial blindness -- Newman's Emory story

Neuro-ophthalmologist Nancy Newman’s 2017 Dean’s Distinguished Faculty Lecture and Award were unexpectedly timely. Her talk on Tuesday was a tour of her career and mitochondrial disorders affecting vision, culminating in a description of gene therapy clinical trials for the treatment of Leber’s hereditary optic neuropathy. The sponsor of those studies, Gensight Biologics, recently presented preliminary data on a previous study of their gene therapy at the American Academy of Neurology meeting in April. Two larger trials Read more

IMSD program nurtures young scientists

The IMSD (Initiative to Maximize Student Development) program nurtures and mentors a diverse group of young scientists at Read more

Flu meeting at Emory next week

We are looking forward to the “Immunology and Evolution of Influenza” symposium next week (Thursday the 25th and Friday the Read more

Cancer

Invasive lung cancer cells have distinct roles

When cancer cells split off from a tumor to seed deadly metastases, they are thought to travel as clusters or packs, a phenomenon known as collective invasion. The members of an invasive pack are not all alike, scientists at Winship Cancer Institute of Emory University have learned.

Lung cancer cells making up an invasive pack have specialized roles as leaders and followers, which depend on each other for mobility and survival, the scientists report in Nature Communications.

The differences between leaders and followers — and their interdependence — could be keys for future treatments aimed at impairing or preventing cancer metastasis, says senior author Adam Marcus, PhD, associate professor of hematology and medical oncology at Winship Cancer Institute and Emory University School of Medicine.

“We’re finding that leader and follower cells have a symbiotic relationship and depend on each for survival and invasion,” he says. “Because metastatic invasion is the deadliest aspect of cancer, our goal is to find agents that disrupt that symbiotic relationship.”

Marcus and former graduate student Jessica Konen, PhD began by observing how a mass of lung cancer cells behaves when embedded in a 3-D protein gel. The cells generally stick together, but occasionally, a few cells extend out of the mass like tentacles, with the leader cell at the tip.

“We saw that when the leader cell became detached or died unexpectedly, the followers could no longer move,” says Konen, now a postdoctoral fellow at MD Anderson. “In one particular movie, we saw a leader cell come out away from the rest of the cells, and then seem to realize that nobody was following him. He actually did a 180, and went back to grab cells to bring with him.” Read more

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Cancer immunotherapy responses in the clinic: T cell revival as predictor

In lung cancer patients who were taking immunotherapy drugs, testing for revived immune cells in their blood partially predicted whether their tumors would shrink. The results were published online by PNAS on April 26.

This finding comes from a small study of 29 patients, who were being treated at Winship Cancer Institute of Emory University with drugs blocking the PD-1 pathway, also known as checkpoint inhibitors.

The study supports a straightforward idea: if tumor-specific CD8 T cells appear to respond to the drug (nivolumab, pembrolizumab or atezolizumab), that’s a good sign. This avenue of investigation may also help researchers figure out why some patients do not benefit from checkpoint inhibitor drugs, and how to combine those drugs with other treatments to increase response rates.

While looking for activated immune cells in the blood is not yet predictive enough for routine clinical use, such tests could provide timely information. Monitoring the immune response could potentially help oncologists and patients decide, within just a few weeks of starting immunotherapy drugs, whether to continue with the treatment or combine it with something else, says co-senior author Suresh Ramalingam, MD, Winship’s deputy director.

“We hypothesize that re-activated CD8 T cells first proliferate in the lymph nodes, then transition through the blood and migrate to the inflamed tissue,” says Rafi Ahmed, PhD, director of the Vaccine Center and a Georgia Research Alliance Eminent Scholar. “We believe some of the activated T cells in patients’ blood may be on their way to the tumor.”

The rest of the Emory Vaccine Center/Winship Cancer Institute press release is here. A few additional points: Read more

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Revived T cells still need fuel

Cancer immunotherapy drugs blocking the PD-1 pathway – known as checkpoint inhibitors – are now FDA-approved for melanoma, lung cancer and several other types of cancer. These drugs are often described as “releasing the brakes” on dysfunctional T cells.

A new study from Emory Vaccine Center and Winship Cancer Institute researchers shows that even if the PD-1-imposed brakes are released, the tumor-specific T cells still need “fuel” to expand in numbers and restore effective immune responses. That fuel comes from co-stimulation through a molecule called CD28.

The results were published Thursday by the journal Science.

Despite the success of PD-1-targeting drugs, many patients’ tumors do not respond to them. The study’s findings indicate that CD28’s presence on T cells could be a clinical biomarker capable of predicting whether drugs targeting PD-1 will be effective. In addition, the requirement for CD28 suggests that co-stimulation may be missing for some patients, which could guide the design of combination therapies.

For the rest of our press release and quotes from authors Rafi Ahmed, Alice Kamphorst and Suresh Ramalingam, please go here. For some additional links and thoughts on PD-1 and CD28, read on:

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Melanoma mutation likes fat for fuel

Cancer cells love glucose, the simple sugar the body uses for energy, so a high-fat, low-carb diet should starve them, right?

Where does this idea come from? Most cancer cells display enhanced glucose uptake, a phenomenon known as the Warburg effect, after 1931 Nobel Prize winner Otto Warburg.

Resurgent interest in exploiting the Warburg effect was described by Sam Apple in NYT Magazine and by Bret Stetka for NPR. High-fat, low-carb “ketogenic” diets are known to be effective against some types of epilepsy, and have also been explored by endurance athletes. Ketogenic diets have been tried as a clinical countermeasure against cancer in a limited way, mainly in brain cancer.

Before everybody gets too excited, let’s think about how particular cancer-driving mutations affect cell metabolism, suggests Winship Cancer Institute researcher Jing Chen. His team’s work in mice suggests that cancers with a common melanoma mutation (BRAF V600E) will grow faster in response to a ketogenic diet. In addition, the Winship researchers found that lipid-lowering agents such as statins curb these cancers’ growth, even in the context of a more normal diet.

The results were published on January 12 in Cell Metabolism.

Caveats: the findings cover just one mutation and need to be tested clinically.

Consumers and cancer patients already get a lot of advice about the right diet to fight cancer, but this research points toward an intriguing concept:  a “precision diet,” tailored to an individual patient’s cancer.  Read more

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Nutty stimulant revealed as anticancer tool

Arecoline — the stimulant component of areca nuts — has anticancer properties, researchers at Winship Cancer Institute of Emory University have discovered. The findings were published Thursday, November 17 in Molecular Cell.

areca-nut-and-arecoline

Areca nut and chemical structure of arecoline. From Wikimedia.

Areca nuts are chewed for their stimulant effects in many Asian countries, and evidence links the practice to the development of oral and esophageal cancer. Analogous to nicotine, arecoline was identified as an inhibitor of the enzyme ACAT1, which contributes to the metabolism-distorting Warburg effect in cancer cells.

Observers of health news have complained that coffee, as a widely cited example, is implicated in causing cancer one week and absolved the next. Arecoline is not another instance of the same trend, stresses senior author Jing Chen, PhD, professor of hematology and medical oncology at Emory University School of Medicine and Winship Cancer Institute.

“This is just a proof of principle, showing that ACAT1 is a good anticancer target,” Chen says. “We view arecoline as a lead to other compounds that could be more potent and selective.”

Chen says that arecoline could be compared to arsenic, a form of which is used as a treatment for acute promyelocytic leukemia, but is also linked to several types of cancer. Plus, arecoline’s cancer-promoting effects may be limited if it is not delivered or absorbed orally, he says. When arecoline first arose in a chemical screen, Chen says: “It sounded like a carcinogen to me. But it all depends on the dose and how it is taken into the body.” Read more

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Bad neighbors cause bad blood -> cancer

Certain DNA mutations in bone cells that support blood development can drive leukemia formation in nearby blood stem cells, cancer researchers have found.

Many cancer-driving mutations are “cell-autonomous,” meaning the change in a cell’s DNA makes that same cell grow more rapidly. In contrast, an indirect neighbor cell effect was observed in a mouse model of Noonan syndrome, an inherited disorder that increases the risk of developing leukemia.

bone-marrow-300

In mouse bone marrow, mesenchymal stem cells (red), which normally nurture blood stem cells, produce a signal that is attractive for monocytes. The monocytes (green) prod nearby blood stem cells to proliferate, leading to leukemia. From Dong et al Nature (2016).

The findings were published Wednesday, October 26 in Nature.

The neighbor cell effect could be frustrating efforts to treat leukemias in patients with Noonan syndrome and a related condition, juvenile myelomonocytic leukemia (JMML). That’s because bone marrow transplant may remove the cancerous cells, but not the cause of the problem, leading to disease recurrence. However, the researchers show that a class of drugs can dampen the cancer-driving neighbor effect in mice. One of the drugs, maraviroc, is already FDA-approved against HIV infection.

“Our research highlights the importance of the bone marrow microenvironment,” says Cheng-Kui Qu, MD, PhD, professor of pediatrics at Emory University School of Medicine, Winship Cancer Institute and Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta. “We found that a disease-associated mutation, which disturbs the niches where blood stem cell development occurs, can lead to leukemia formation.”

Editorial note: This Nature News + Views, aptly titled “Bad neighbors cause bad blood,” explains JMML, and how the relapse rate after bone marrow transplant is high (about 50 percent). It also notes that a variety of genetic alterations provoke leukemia when engineered into bone marrow stromal cells in mice (like this), but Qu and his colleagues described one that is associated with a known human disease.

Noonan syndrome often involves short stature, distinctive facial features, congenital heart defects and bleeding problems. It occurs in between one in 1000 to one in 2500 people, and can be caused by mutations in several genes. The most common cause is mutations in the gene PTPN11. Children with Noonan syndrome are estimated to have a risk of developing leukemia or other cancers that is eight times higher than their peers.
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Immunotherapy for triple negative breast cancer

Treatments that unleash the immune system against cancer have been a hot topic for the last few years, but they do not appear in our recent feature on breast cancer for Winship Cancer Institute’s magazine.

Partly, that’s because decent avenues for treatment exist for most types of breast cancer, with improvements in survival since the 1980s. Immunotherapy’s successes have been more dramatic for types of cancer against which progress had been otherwise meager, such as lung cancers and metastatic melanoma.

Jane Meisel, MD with patient

Winship oncologist Jane Meisel, MD with patient

However, for “triple-negative” breast cancer (TNBC) in particular, immunotherapy could be a good match, because of the scarcity of targeted treatments and because TNBC’s genomic instability may be well-suited to immunotherapy.

Winship oncologists Jane Meisel and Keerthi Gogineni inform Lab Land that several early-phase clinical studies open to breast cancer patients, testing “checkpoint inhibitor” agents such as PD-1 inhibitors, are underway. More are pending.

Meisel’s presentation at Winship’s Sea Island retreat says that immunotherapy is “not yet ready for prime time, but a very promising experimental approach for a subset of patients for whom current therapies are not sufficient. We need to better understand which subsets of patients are most likely to benefit, and how we can use other therapies to enhance efficacy in patients who don’t initially respond.”

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Anticancer strategy: expanding what is druggable

Scientists at Winship Cancer Institute, Emory University have identified compounds that stop two elusive anticancer targets from working together. In addition to striking two birds with one stone, this research could expand the envelope of what is considered “druggable.”

fx1-1Many of the proteins and genes that have critical roles in cancer cell growth and survival have been conventionally thought of as undruggable. That’s because they’re inside the cell and aren’t enzymes, for which chemists have well-developed sabotage strategies.

In a twist, the potential anticancer drugs described in Cancer Cell disable an interaction between a notorious cancer-driving protein, MDM2, and a RNA encoding a radiation-resistance factor, XIAP.

The compounds could be effective against several types of cancer, says senior author Muxiang Zhou, MD, professor of pediatrics (hematology/oncology) at Emory University School of Medicine and Aflac Cancer and Blood Disorders Center.

In the paper, the compounds show activity against leukemia and neuroblastoma cells in culture and in mice, but a fraction of many other cancers, such as breast cancers (15 percent) and sarcoma (20 percent), show high levels of MDM2 and should be susceptible to them.

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Outcomes in minimally invasive lung cancer surgery

To accompany our recent article on minimally invasive lung surgery for Winship magazine, please find a video featuring thoracic surgeon Manu Sancheti, MD.

As Sancheti explains, an advantage of minimally invasive approaches (sometimes called VATS for video-assisted thoracic surgery) is that surgeons do not open the patient’s chest, avoiding pain and potential complications and reducing length of stay in the hospital.

Among thoracic surgeons, the shift to this type of approach has taken place in the last few years — unevenly. Here’s a graph froLung surgery graphm one recent publication from Felix Fernandez, MD and colleagues, showing the percent of stage I lung cancer surgeries — compiled for individual surgeons in the Society of Thoracic Surgeons  — that are minimally invasive from 2011-2014. The average is about 63 percent, but it varies widely.

Attention medical journalists: if you want to ask questions like “Are these minimally invasive lung surgery approaches really good for long term patient outcomes?”, Fernandez is your guy. As the numbers come in, he is leading a team that is analyzing them. Read more

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FDA approves Emory-developed cancer imaging probe

A cancer imaging agent that was originally developed at Emory was approved on Friday, May 27 by the U.S. Food and Drug Administration.

Axumin, a PET (positron emission tomography) imaging agent, is indicated for diagnosis of recurrent prostate cancer in men who have elevated PSA levels after previous treatment. Axumin, now being commercialized by UK-based Blue Earth Diagnostics, is also known as 18F-fluciclovine or FACBC (an abbreviation for anti-1-amino-3-[18F]fluorocyclobutane-1- carboxylic acid).

goodman-schuster

Mark Goodman, PhD (left) and David Schuster, MD (right)

Imaging using axumin/fluciclovine is expected to help doctors detect and localize recurrent prostate cancer, and could guide biopsy or the planning of additional treatment. Fluciclovine was originally developed at Emory by Mark Goodman and Timothy Shoup, who is now at Massachusetts General Hospital.

The earliest research on fluciclovine in the 1990s was on its use for imaging brain tumors, and it received a FDA “orphan drug” designation for the diagnosis of glioma in 2015. About a decade ago, Emory researchers stumbled upon fluciclovine’s utility with prostate cancer, while investigating its activity in a patient who appeared to have renal cancer, according to radiologist David Schuster, who has led several clinical studies testing fluciclovine.

“This led us to see if this radiotracer would be good for looking at prostate cancer, specifically because of its low native urinary excretion,” Schuster is quoted as saying in the radiology newsletter Aunt Minnie. “If you look at the history of medical science, it is taking advantage of the unexpected.”

Early research on the probe was supported by Nihon Mediphysics, and later support for clinical research on FACBC/fluciclovine came from the National Cancer Institute, the Georgia Research Alliance and the Georgia Cancer Coalition. [Both Emory and Goodman are eligible to receive royalties from its commercialization]. Additional information here.

References for two completed studies on fluciclovine in recurrent prostate cancer

Odewole OA et al. Comparison with CT imaging (2016) 

Schuster DM et al. Head to head comparison with ProstaScint (2014). Read more

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